Diamine Teal is one of my favorite inks. I’ll be pretty upfront about it.
I love the color of this ink. It’s a very classy dark blue-green, almost like a blue-black. I think you can use this in pretty much any situation: I’ve written in-class essays with this ink, and I’ve written letters to penpals with this ink. It’s well-behaved, like most of the Diamine inks I’ve used, and I’ve put it in several different pens. I think it would be great with a broader nib or a flex nib so you can show off how it shades, but it works quite well in thinner nibs as well. Honestly, I have very little trouble with it. I think cleaning is a little bit more difficult, but I feel like this is more a factor of how dark it is rather than factor of it being a misbehaving ink.
I really like how you can get a little bit of shading, but not necessarily in the way you would think. When this ink is put down on the page lightly, it’s more of a light blue: when it’s put down heavier, it’s a dark blue-green. Here are two samples done with a Nikko spoon nib and a Nikko G nib on Tomoe River paper. A spoon nib lays ink down more consistently and with a thinner line, while the G nib has more flex and lays down more ink.There’s only very slight bleedthrough on Tomoe River, but keep in mind that dip pens lay down a lot of ink! Diamine Teal is very well behaved on Rhodia and Tomoe alike: no bleedthrough and very little showthrough when in a normal fountain pen, whether extra fine or double broad.
Please note that the colors present in this review may not be perfectly true to life: there will be color differences between monitors. Scans I post online are as close as I can possibly get them to the ink that I have. Please keep this in mind, as different factors (such as whether or not the bottle was shaken, the pen used, the paper used, the lighting in the room, etc.) could affect the color!
I’m not at all affiliated with JetPens or Goulet Pens: just a happy customer!